Mars
* 
Rage, acting as a pseudo-
Black King Bar, completely negates Mars' initiation if used in time.
* 
Feast does damage and heals based on max health, perfect against high-health strength heroes like Mars.
* 
Infest allows Lifestealer to potentially save allies from Mars' initiation with a quick burst of extra health.
Mars
* 
Burning Spear's magical damage is very troublesome for Mars in the laning stage.
* 
Life Break's percentage-based magical damage bypasses Bulwark, and can also be used to jump in or out of Arena Of Blood.
Mars
* 
Arcane Orb's pure damage ignores Mars' Bulwark.
* 
Astral Imprisonment can be used to stop Mars from being disruptive or save allies from his abilities.
* 
Sanity's Eclipse deals high damage to Mars, due to his low intelligence pool.
Mars
* 
Decay, 
Soul Rip and 
Flesh Golem all deal magical damage which ignores Bulwark.
* Decay reduces Mars' natural strength and therefore his health pool, which is what he relies on to trade effectively in lane.
Mars
* Solar Guardian can save allies caught inside 
Arena of Blood.
Mars
* 
Nether Blast, 
Decrepify and 
Life Drain deal high magical damage and bypasses Bulwark.
* 
Nether Ward reduces the amount of abilities Mars can use during fights and forces Mars to be careful about the heavy mana cost of Arena Of Blood.
* Pugna is one of few heroes that can contest Mars' ability to push and defend towers early on.
Mars
* It is difficult for Mars to trade blows with Ogre Magi in the early game thanks to his high base health, resistance and 
Ignite.
* 
Bloodlust can assist Ogre Magi or an ally in repositioning against Mars for its move speed bonus.
* 
Fireblast can interrupt and mitigate Mars from performing his skill combos, especially in combination with 
Multicast.
Mars
* Mars' own father is a formidable foe because Zeus deals massive amounts of magical damage. The high damage, low cooldown nukes of 
Arc Lightning and 
Lightning Bolt combined with the percent health magic damage of 
Static Field will shred Mars' health because it bypasses Bulwark completely.
Mars
* Necrophos' largely magical damage completely ignores Bulwark.
* 
Ghost Shroud protects Necrophos from God's Rebuke but more importantly stops Mars from being a threat in lane.
Mars
* Venomancer's spells all deal magical damage, ignoring Bulwark.
* Venomancer's multiple slows are especially effective at kiting Mars.
* 
Plague Ward can attack through Arena Of Blood.
Additional:
* Venomancer's poison attacks are all magical damage, ignoring 
Bulwark.
* Venomancer's multiple slows are especially effective against Mars' low mobility.
* Plague Wards can attack through Arena of Blood.
Mars
* Time Dilation while 
Spear of Mars and 
God's Rebuke are on cooldown will make these abilities unusable for a long time, rendering Mars nearly useless.
* Mars cannot turn inside the Chronosphere, which makes it easy to attack him from the back, bypassing Bulwark completely.
Additional:
* 
Time Walk allows Faceless Void to escape or enter Arena Of Blood, and helps him recover from Mars' burst damage.
* 
Time Lock's magical damage ignores Bulwark.
* 
Chronosphere allows Faceless Void to reposition behind Mars, ignoring his Bulwark while he is helplessly frozen in time.
Mars
* 
Snowball can protect Tusk and his teammates from a Spear of Mars' stun after an Arena of Blood, and with proper targeting, even bring them out of the Arena. This is especially noticeable in the earlier stages of the game before allies buy Black King Bar and rely on this less. Even during the late-game, Tusk can purchase a 
Blink Dagger to save allies that are caught before Black King Bars can be used by Blinking in and Snowballing out.
* 
Tag Team is a constant threat to Mars in-lane, as it deals significant damage and slow, making Bulwark slightly ineffective.
* It is worth noting that 
Ice Shards can be detrimental to Tusk's own team by creating terrain that Spear of Mars can latch on, though using it conservatively is a good enough solution in most cases.
Mars
* 
Ball Lightning makes it almost impossible to catch Storm Spirit without someone else initiating for you.
* 
Overload is not reduced by Bulwark and the magical damage spam can wear down Mars quickly.
Additional:
* Storm Spirit's abilities all do magical damage, which can bypass Bulwark.
* Ball Lightning can escape through Arena of Blood and it is easy to dodge Spear of Mars.
Mars
* 
Shadowraze deals magic damage and ignores Bulwark.
* 
Requiem of Souls deals magic damage and can fear Mars away, forcing him to turn around and therefore become vulnerable.
Mars
* 
Nethertoxin breaks the damage block from Bulwark.
* 
Poison Attack and 
Viper Strike's slows make it difficult for Mars to contribute to fights due to his low mobility.
Additional:
* Viper Strike can disable Bulwark entirely, making Mars far less tanky. Using Nethertoxin inside Arena of Blood may discourage enemies from following up with Mars's initiation.
* 
Rod of Atos is currently common on Viper and keeps Mars in position long enough to be killed.
* However, Viper is not very tanky earlier in the game, so positioning against Mars is important for Viper since a well-timed Spear of Mars can be the end of Viper.
Mars
* Rebound allows her to jump in or out of the Arena Of Blood. She can save her allies from the Arena with Dispose as well.
Mars
* 
Swashbuckle is an auto attack and therefore ignores Mars' Bulwark.
* 
Shield Crash upgraded with Aghanim is an auto attack and therefore ignores Mars' Bulwark.
* 
Rolling Thunder makes him immune to magic, making Pangolier able to roll in and out of Mars' Arena Of Blood.
Mars
* 
Sticky Napalm slows turn rate, making it difficult for Mars to face frontwards, where Spear of Mars and Bulwark are effective. In combination with 
Firefly, which deals magic damage, Batrider can make quick work of Mars.
* 
Flaming Lasso disables Mars while enemies re-position themselves behind Mars to avoid Bulwark.
Mars
* 
Dragon Slave deals reliable magic damage during the laning phase against Mars.
* Lina's 
Eul's Scepter of Divinity and 
Light Strike Array combo can interrupt Mars from being disruptive for a decent amount of time and leave him vulnerable for follow up stuns.
* 
Laguna Blade deals massive magical damage, and pure damage with 
Aghanim's Scepter.
Mars
* Heroes with high magical or pure damage will bypass Bulwark: 
Timbersaw, 
Dark Willow, 
Enigma, 
Invoker, 
Pugna, 
Skywrath Mage, 
Tinker, 
Zeus, 
Oracle.
Mars
* Nukers who have set amounts of damage will really struggle against Lone Druid especially in True Form: 
Puck, 
Void Spirit, 
Mars.
Mars
* Heroes that can save their allies can be a big problem for Mars: 
Dazzle, 
Omniknight.
Mars
* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.
Mars
* Heroes with high health especially Strength heroes will take more damage on Sun Ray: 
Axe, 
Pudge, 
Bristleback, Mars.
Mars
* Heroes that depend on disrupting fights with ability combos or big ultimate abilities are vulnerable to the long stun of Fiend's Grip: 
Disruptor, 
Death Prophet, Enigma, 
Faceless Void, Invoker, 
Lich, 
Magnus, Mars, 
Medusa, 
Outworld Destroyer, 
Phoenix, Puck, 
Queen of Pain, 
Shadow Fiend, 
Treant Protector, 
Underlord, 
Winter Wyvern, 
Witch Doctor, Zeus.
Mars
* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.
Mars
* 
Ursa is a special mention because despite Bulwark diminishing most of the damage Ursa does, he is quite durable, especially with 
Enrage, discouraging the aggressive all-in playstyle of Mars; Ursa can simply not target Mars.
Mars
* Heroes that can save their allies can be a big problem for Mars: Dazzle, Omniknight.
Mars
* 
Kunkka's 
Ghostship and 
Torrent disrupt fights in Arena Of Blood.
Mars
* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.
Mars
* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.
Mars
* Heroes with break abilities: 
Shadow Demon (with Aghanim's Scepter), 
Viper.
Mars
* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.
Mars
* 
Berserker's Call forces Mars to face in the direction choosen.
* 
Counter Helix deals pure damage and can go through Bulwark.
Primal Beast
* Long lockdown is a great way to deal with Axe to prevent Berserker's Call from being used, heroes such as 
Legion Commander, 
Beastmaster and 
Primal Beast are good examples of this.
Mars
* 
Blink Strike gives bonus backstab damage and can bypass Bulwark. Defensively, it could be used to teleport away from Mars, especially while inside Arena of Blood.
* 
Smoke Screen can interrupt Mars' skill combos, especially when cast inside Arena of Blood.
* 
Tricks of the Trade can be used to evade Mars' skills, which have a slight delay to them. It could also be used to buy himself time while trapped inside of Arena of Blood.
Additional:
* Bulwark is generally irrelevant against Riki as he primarily deals bonus damage from behind.
Mars
* Heroes who rely on their target to run away: 
Riki, 
Bounty Hunter.
Mars
* 
Firestorm and 
Pit of Malice are very disruptive in team fights, completely matching Mars especially since it can all be cast inside Arena Of Blood and also does percentage-based magical damage, negating Bulwark.
* 
Dark Rift can save any allies of Underlord trapped in Arena Of Blood.
* 
Atrophy Aura allows Underlord to lane against Mars quite well since he does not have the best base damage during the early game.
* Underlord is a common carrier of both 
Pipe of Insight and 
Mekansm/
Guardian Greaves, allowing his team to combat Mars in the mid to late game.
Mars
* Heroes with strong area-of-effect damaging and/or disabling abilities will be able to intercept Underlord and his team when they exit from Fiend's Gate: 
Luna's Aghanim's Scepter upgraded 
Eclipse, 
Dawnbreaker's 
Solar Guardian, Axe's Berserker's Call, Mars's Arena of Blood, 
Jakiro's 
Macropyre, 
Dual Breath and 
Ice Path, 
Naga Siren's 
Song of the Siren, 
Razor's 
Eye of the Storm and 
Plasma Field, 
Lina's Light Strike Array, 
Broodmother's 
Spinner's Snare from Aghanim's Scepter, 
Elder Titan's 
Earth Splitter and 
Echo Stomp, 
Alchemist's 
Unstable Concoction and 
Acid Spray, Queen of Pain's 
Sonic Wave, 
Dark Seer's 
Wall of Replica and 
Vacuum, 
Venomancer's 
Noxious Plague and 
Poison Nova from Aghanim's Scepter, Oracle's 
Fortune's End and 
Rain of Destiny from 
Aghanim's Shard, 
Bloodseeker's 
Blood Rite, Enigma's 
Black Hole and 
Midnight Pulse, Shadow Fiend's Requiem of Souls, 
Batrider's Aghanim's Scepter upgraded Flaming Lasso, Firefly, 
Flamebreak and Sticky Napalm, 
Ancient Apparition's 
Ice Blast, 
Sand King's 
Epicenter, 
Sand Storm and 
Burrowstrike, 
Gyrocopter's 
Call Down, 
Ember Spirit's 
Sleight of Fist, Death Prophet's 
Exorcism and 
Silence, 
Monkey King's 
Wukong's Command, 
Crystal Maiden's 
Freezing Field, 
Muerta's 
The Calling, Medusa's 
Stone Gaze, Zeus's 
Nimbus from Aghanim's Scepter. Dark Willow's 
Bramble Maze, 
Pangolier's Swashbuckle, 
Grimstroke's 
Soulbind, 
Ink Swell and 
Stroke of Fate, 
Earthshaker's 
Echo Slam and 
Fissure, Puck's 
Dream Coil and 
Waning Rift, Winter Wyvern's 
Winter's Curse, Magnus's 
Reverse Polarity.
Mars
* Even if he can slow Mars down with 
Shrapnel and 
Headshot, Mars can tank Sniper's physical damage simply by facing him with Bulwark, allowing him to endure his auto-attacks into the late-game. Should Sniper choose to attack someone else, Mars can redirect his projectiles with Bulwark's active ability.
* Sniper's poor mobility makes him very vulnerable to Arena of Blood, especially in the early game. Mars can also take advantage of this by pushing him closer to the front line with Spear of Mars.
Primal Beast
* Heroes who have high health are a problem for Sniper because he likes to attack the closest target and sit at the back, much like a 
Terrorblade so when that hero doesn't die; he's forced to show his position for a very long time: 
Centaur Warrunner, Legion Commander, Primal Beast.
Mars
* Bulwark negates most of the physical damage from Terrorblade and his illusions.
* God's Rebuke and Spear of Mars can decimate Terrorblade's illusions quickly.
Primal Beast
* Heroes with abilities that can lock down Terrorblade and prevent him from using Sunder: 
Bane, Batrider, Earthshaker, Elder Titan, Faceless Void, Invoker, Legion Commander, Mars, Primal Beast, Riki, 
Shadow Shaman, 
Silencer, 
Vengeful Spirit, Void Spirit.
Mars
* As long as Mars is facing her with Bulwark, even if pushed away with 
Gust, Drow Ranger will do no effectual damage against him. Mars' ability to endure her onslaught usually gives him enough time to cast Arena of Blood, of which she has a very slim chance surviving without Gust.
* With Bulwark's active ability, Mars can protect allies pursued by Drow Ranger by redirecting her projectiles to his shield instead.
Primal Beast
* Heroes who have low or high armor but very high health will be difficult for drow to burst down quickly: Primal Beast, Axe, Centaur Warrunner.
Mars
* Durable heroes: Axe, Dawnbreaker, Bristleback, Mars, Omniknight, 
Tidehunter, 
Wraith King, Primal Beast, Underlord.
Primal Beast
* Durable heroes: Axe, Dawnbreaker, Bristleback, Mars, Omniknight, Tidehunter, Wraith King, Primal Beast, Underlord.
Mars
* Phantom Assassin's high physical damage is greatly reduced by Bulwark.
* God's Rebuke has true strike, ignoring the evasion from 
Blur.
Mars
* If visible, Mars can knock Monkey King off his 
Tree Dance with God's Rebuke, as well as Spear of Mars. Arena of Blood also destroys a large swath of trees, which can disrupt Monkey King's positioning and turn him vulnerable should he choose to hide in trees.
* Mars can endure 
Jingu Mastery attacks simply by facing him with Bulwark.
* Mars can end Wukong's Command early by displacing Monkey King with a well-thrown Spear of Mars. Mars can also endure most of his clones with Bulwark.
Additional:
* Monkey King's natural reliance on trees makes him an exceptionally prime target for Spear of Mars. Should Monkey King use Mischief to disguise himself, it will still hit him, stunning him in the process.
* God's Rebuke easily pushes Monkey King out of Wukong's Command.
Mars
* 
Shukuchi cannot help Weaver escape from Arena of Blood, and can most likely die if detected through invisibility.
* If pinned to the arena's walls, 
Time Lapse tends to not be enough to save Weaver, as God's Rebuke can keep him burst down thanks to its damage scaling.
* 
The Swarm and 
Geminate Attack are not enough to pierce through Bulwark.
Mars
* Bulwark blocks much of Slark's basic attack damage, even during 
Shadow Dance.
* Slark finds it very difficult to have a good early/mid game when pressured in the early game by Spear of Mars and God's Rebuke.
* Spear of Mars and God's Rebuke can hit Slark through Shadow Dance and 
Depth Shroud.
* Should 
Pounce be on cooldown, Slark is very vulnerable inside Arena of Blood.
Mars
* Arena Of Blood prevents Bloodseeker from attacking a 
Ruptured target.
* Bulwark helps Mars survive Rupture ganks simply by turning towards Bloodseeker without moving.
* Spear of Mars and God's Rebuke can push Bloodseeker from Ruptured targets.
Mars
* Spectre cannot have a good game if she is pressured heavily in lane, which is something Mars can do. He may even force her to cast 
Haunt as an escape, putting it on a long cooldown.
* Should Spectre get to the late game, Mars can block a large amount of her damage with Bulwark and can mitigate some of the chaos caused by her Haunt illusions with God's Rebuke.
Mars
* Bulwark mitigates 
Omnislash which deals physical damage, severely reducing its damage.
* Omnislash switch to opposite direction with each slash, so Mars can easily reduce most of its damage.
* However because {Ability ID:Blade Fury|Juggernaut} gives spell immunity Juggernaut can easily escape from {Ability ID:Arena Of Blood|Mars}.
Additional:
* Juggernaut deals mostly physical damage, which is easily mitigated with Bulwark.
* Juggernaut's Omnislash switches to opposite directions which each slash, so Mars can mitigate most of its damage since he only takes full damage from one direction: his back.
Mars
* Bulwark blocks the attack from Meepo and his clones.
* Spear of Mars & God's Rebuke prevents Meepo and his clones from initiation or escaping.
Mars
* Heroes who can disable Mars but cannot do any damage to him, meaning he just tanks their abilities: 
Doom, Magnus.
Mars
* Heroes with forced movement abilities or non-interrupting forced movement, such as 
Lion, 
Drow Ranger, Magnus, Mars, as they can cancel blast-off mid air, removing his ability to initiate or escape.
Mars
* Heroes who lack burst damage will have a hard time against Mars: 
Phantom Lancer, 
Nature's Prophet, Lich.
Mars
* Heroes who cannot fight back during Arena of Blood in the early and mid game: 
Abaddon, 
Anti-Mage, Broodmother, Luna, 
Sniper, 
Troll Warlord, 
Weaver, 
Clinkz.
Mars
* Heroes that can negate Hoodwink's mobility: Kunkka, Disruptor, Mars.
Mars
* Heroes who lack burst damage will have a hard time against Mars: Phantom Lancer, Nature's Prophet, Lich.
Mars
* Any hero who can counter-initiate in anticipation without getting caught in Reverse Polarity: 
Sven, Omniknight, Enigma, Luna, Naga Siren, Mars, Jakiro, Venomancer, Elder Titan, Faceless Void, 
Rubick, 
Keeper of the Light, Pugna, Invoker, 
Spectre, Alchemist, Treant Protector, Lina, Oracle, Zeus, Shadow Shaman, Phoenix, Razor, 
Huskar, Batrider, Kunkka, Tidehunter, Wraith King, Sand King, Medusa, Dawnbreaker.
Mars
* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Luna, Sniper, Troll Warlord, Weaver, Clinkz.
Mars
* Heroes with the capability of removing or destroying trees greatly hinders the effectiveness of Treant Protector's abilities: Batrider, Nature's Prophet, Lina, Enigma, Mars
Mars
* Heroes who lack burst damage will have a hard time against Mars: Phantom Lancer, Nature's Prophet, Lich.
Mars
* Heroes that are hard to gank: 
Dragon Knight, Mars, Centaur Warrunner.
Mars
* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Luna, Sniper, Troll Warlord, Weaver, Clinkz.
Mars
* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Luna, Sniper, Troll Warlord, Weaver, Clinkz.
Mars
* Heroes who rely on their target to run away: Riki, Bounty Hunter.
Mars
* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Luna, Sniper, Troll Warlord, Weaver, Clinkz.
Mars
* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Luna, Sniper, Troll Warlord, Weaver, Clinkz.
Mars
* Heroes that are hard to gank: Axe, Death Prophet, Phantom Lancer, 
Slark, Centaur Warrunner, Bristleback, Medusa, Mars.
Mars
* Legion Commander is both good and bad vs Mars, on the plus side she can dispel Spear of Mars with 
Press the Attack and is a good 
Silver Edge carrier. However, Mars is not an ideal 
Duel target, as Bulwark will force her to 1: Buy Silver Edge, and 2: Hit Mars with it before the Duel, allowing a skilled Mars to react, especially with Eul's Scepter of Divinity. In teamfights, Mars will happily draw attention after using his abilities, and tank the Duel with all spells on cooldown.
Mars
* Because Duel requires both combatants to face each other, Bulwark's effectiveness will be increased by a huge margin, which makes it much more difficult for Legion Commander to win any duels against him.
* Spear of Mars and God's Rebuke pushes Legion Commander away during Duels against allies.
Additional:
* Bulwark immensely mitigates Duel, even with bonus physical damage, as Bulwark scales by percentage. Mars can also buy time for a dueled ally by pushing Legion Commander away with Spear of Mars.
Mars
* Medusa's Stone Gaze forces Mars to choose between getting petrified, or turning his vulnerable back on Medusa.
Mars
* Bulwark can make each of Medusa's attacks target him instead, reducing Medusa's contribution on team fights.
* Spear of Mars stuns Medusa and also pushes her away from teamfights, taking advantage of Medusa's low mobility.
* Arena Of Blood blocks Medusa's attacks from outside the arena.
Mars
* Heroes with high magical or pure damage will bypass Bulwark:
Timbersaw, 
Dark Willow, 
Enigma, 
Invoker, 
Pugna, 
Skywrath Mage, 
Tinker, 
Zeus, 
Oracle.
Primal Beast
* Oracle can negate and shut down Primal Beast simply with Fate's Edict, especially in the early game, as a majority of his damage-dealing spells are magic.
Onslaught charge with a well-timed Fortune's End.
* Oracle can interrupt Primal Beast's
* Primal Beast's lethal burst damage combos can be further stalled with False Promise; combined with Fate's Edict and regen from Purifying Flames, Oracle can even completely negate Primal Beast's offense.